1. Field of the Invention
This invention relates generally to energy-storage devices, and relates more particularly to high-permittivity ceramic components utilized in an array configuration for application in ultrahigh-electrical-energy storage devices.
2. Description of the Relevant Art
The internal-combustion-engine (ICE) powered vehicles have as their electrical energy sources a generator and battery system. This electrical system powers the vehicle accessories, which include the radio, lights, heating, and air conditioning. The generator is driven by a belt and pulley system and some of its power is also used to recharge the battery when the ICE is in operation. The battery initially provides the required electrical power to operate an electrical motor that is used to turn the ICE during the starting operation and the ignition system. The most common batteries in use today are flooded lead-acid, sealed gel lead-acid, Nickel-Cadmium (Ni-Cad), Nickel Metal Hydride (NiMH), and Nickel-Zinc (Ni-Z). References on the subject of electrolchemical batteries include the following: Guardian, Inc., “Product Specification”: Feb. 2, 2001; K. A. Nishimura, “NiCd Battery”, Science Electronics FAQ V1.00: Nov. 20, 1996; Ovonics, Inc., “Product Data Sheet”: no date; Evercel, Inc., “Battery Data Sheet-Model 100”: no date; S. R. Ovshinsky et al., “Ovonics NiMH Batteries: The Enabling Technology for Heavy-Duty Electrical and Hybrid Electric Vehicles”, Ovonics publication 2000-01-3108: Nov. 5, 1999; B. Dickinson et al., “Issues and Benefits with Fast Charging Industrial Batteries”, AeroVeronment, Inc. article: no date.
Each specific type of battery has characteristics, which make it either more or less desirable to use in a specific application. Cost is always a major factor and the NiMH battery tops the list in price with the flooded lead-acid battery being the most inexpensive. Evercel manufactures the Ni-Z battery and by a patented process, with the claim to have the highest power-per-pound ratio of any battery. See Table 1 below for comparisons among the various batteries. What is lost in the cost translation is the fact that NiMH batteries yield nearly twice the performance (energy density per weight of the battery) than do conventional lead-acid batteries. A major drawback to the NIMH battery is the very high self-discharge rate of approximately 5 to 10% per day. This would make the battery useless in a few weeks. The Ni-Cad battery as does the lead-acid battery also has self-discharge but it is in the range of about 1% per day and both contain hazardous materials such as acid or highly toxic cadmium. The Ni-Z and the NiMH batteries contain potassium hydroxide and this electrolyte in moderate and high concentrations is very caustic and will cause severe burns to tissue and corrosion to many metals such as beryllium, magnesium, aluminum, zinc, and tin.
Another factor that must be considered when making a battery comparison is the recharge time. Lead-acid batteries require a very long recharge period, as long as 6 to 8 hours. Lead-acid batteries, because of their chemical makeup, cannot sustain high current or voltage continuously during charging. The lead plates within the battery heat rapidly and cool very slowly. Too much heat results in a condition known as “gassing” where hydrogen and oxygen gases are released from the battery's vent cap. Over time, gassing reduces the effectiveness of the battery and also increases the need for battery maintenance, i.e., requiring periodic deionized or distilled water addition. Batteries such as Ni-Cad and NiMH are not as susceptible to heat and can be recharged in less time, allowing for high current or voltage changes which can bring the battery from a 20% state of charge to an 80% state of charge in as quick as 20 minutes. The time to fully recharge these batteries can take longer than an hour. Common to all present day batteries is a finite life and if they are fully discharged and recharged on a regular basis their life is reduced considerably.